add option for deformable rigid split impulse

src/BulletSoftBody/btDeformableContactProjection.h

@@ -60,9 +60,12 @@ public:
     // add friction force to the rhs of the linear solve
     virtual void applyDynamicFriction(TVStack& f);
     
-    // update the constraints
+    // update and solve the constraints
     virtual btScalar update();
     
+    // solve the position error using split impulse
+    virtual btScalar solveSplitImpulse(const btContactSolverInfo& infoGlobal);
+    
     // Add constraints to m_constraints. In addition, the constraints that each vertex own are recorded in m_constraintsDict.
     virtual void setConstraints();
     
@@ -70,5 +73,7 @@ public:
     virtual void setProjection();
     
     virtual void reinitialize(bool nodeUpdated);
+    
+    virtual void splitImpulseSetup(const btContactSolverInfo& infoGlobal);
 };
 #endif /* btDeformableContactProjection_h */